​Having been charged with preserving the Wolfriders while the majority of them go off to recover the shards of the palace from humans, the newly fledged chief Ember and her small band—Leetah, Skywise, Pike, Moonshade, Redlance, Nightfall, Dewshine, Scouter, and pregnant Tyleet, along with their respective wolves—embark on a quest for a new Holt.

At first, every decision is a test for Ember, as she struggles to determine which direction to take and how to find shelter in the open plains through which the band is traveling. To make matters worse, Moonshade freely expresses her doubts about and displeasure over Ember’s choices. It takes a series of dangerous encounters and a bout of insect-induced hallucination for Ember to understand and deal with Moonshade’s distress. Ember’s first chance to really shine comes when a period of bad hunting for the elves leads her to consider a source of food that they would have otherwise overlooked: mice.

Finally, the small band arrives at an island of rock in the ocean of grass. Though it had been inhabited, it seems deserted now, and the many caves and proximity to water make it a serious candidate for the new Holt. The discovery of a small spire shaped like a howling wolf settles the Wolfriders’ minds. However, as they start to move in, they are approached by a strange elf who can make himself invisible to the Wolfriders’ senses. He is Teir, beast-friend and loner who has lived among the rocks for many years with only animals to keep him company. Most of the Wolfriders take to him immediately; only Skywise is suspicious and wary. Teir stays distant from the little tribe at first, but gradually he begins to interact with them. Indeed, he and Ember are attracted to one another, though neither admits it. More urgently, the peaceful settling-in process is disturbed when a horribly mutated wolf attacks the Wolfriders during a hunt.

As the Wolfriders discuss whether to stay at Howling Rock after the appearance of the shapechanged wolf, Ember walks out on the council to follow Timmain back to Teir. He shows her his ability to mimic animals and make them trust him. He also tells her of his past: he is actually a Go-Back. Later, Skywise is plagued by dreams of his lost wolf blood, with Teir as a central figure. His distrust of Teir doesn't sit well with Ember. Skywise and Ember verbally spar, leaving Ember feeling she isn't fit to be chief. A vision of an earlier chieftess, Huntress Skyfire, helps her sort out what she's doing wrong.

With more horrible news from the Shards war resonating among the elves, Skywise, Dewshine, and Pike go on a ride-out to see what's what. Something seems to be agitating the game--and something seems to be driving it toward Howling Rock. The scouting party finds out quickly enough when they stumble on a passel of mutated creatures and are forced to fight them. The creatures ignore Skywise, so he is able to kill them after the others are incapacitated. The other elves fetch the wounded, and Leetah heals them.​Skywise is convinced that Teir is behind it all, and Ember decides to find out once and for all. She rides off to confront him alone. (At the same time, Skywise and Timmain accompany Aroree back to the human city, as Timmain is needed to help put the Palace together again.) Dodging mutated monsters, Ember comes across Teir, who is distracted by someone calling inside his head. He doesn't seem to be responsible for the new monsters; indeed, when they are attacked and Ember is hurt, he defends her.

As Teir carries Ember back to the Holt, Leetah and Nightfall intercept him. They automatically assume he's responsible for her injuries, and, after bringing Ember back from the precipice, they warn Teir not to follow them. Teir isn't so easily discouraged, though, and follows at a distance. When more shapechanged monsters arrive, Teir makes them attack one another, to prove that he's on the Wolfriders' side. However, in doing so he opens himself up to the voice that's been calling him, and he collapses. Leetah goes to him “to learn [his] heart" and mentally discovers the horrible, intelligent mutated bear--created by Winnowill, as were all of the other monsters--that is trying to feed off Teir's powers. At last accepting his innocence in the matter of the mutated beasts, the Wolfriders bring him into the Holt and make him comfortable. Leetah must keep him asleep, though, to protect him from his enemy.

Soon the Holt is surrounded by many monsters, led by the mutated bear, who demands Teir and threatens slaughter if the loner is not delivered. Ember makes the painful decision to sacrifice Teir to save the tribe. They strap the sleeping elf to a litter, and Dewshine, riding her wolf-friend Longshanks, races down to deposit the body among the monsters. Of course, the monsters have no intention of letting her leave, and she barely escapes. Longshanks is killed in his valiant attempt to get her back, and she is bitten by poisonous snakes, but Scouter arrives to pull her to safety, and Leetah is able to purge her veins of the poison.

The mutated bear easily overwhelms Teir's mind and joins with him. It broadcasts its dreadful intent: it wants the death of all wolf-blooded elves. The monsters attack! The Wolfriders fight ferociously, but the odds are overwhelming. There is one slim chance, however: Leetah has the same sort of magic as Winnowill, and the monsters implicitly trust her; Ember tells her that she must kill their leader. Leetah approaches him, and touches minds with him to see the true purpose for Winnowill's creation of the monsters: to destroy all wolf-blooded elves. This angers Leetah enough to motivate her to kill him magically. She then heals Teir who is on the verge of death. But because the monster's mind was linked with Teir's when Leetah killed the monster, Teir's mind was affected as well and he can no longer send. Ember, afraid that more of Winnowill's monsters will come seeking Teir and the Wolfriders if Teir regains his sending powers, she gives him a choice: to be fully healed by Leetah and separate himself from the Wolfriders, or to stay with them but not regain his sending powers. He is extremely frustrated by this decision, and he and Ember get into an argument. But as they both express their frustrations, they come to an understanding and give in to their attraction to each other.​The next day, Teir announces that he will take the healing and return to his solitary life with animals. After he is healed, the Palace appears. As all of Ember's group of elves prepare to reunite with Cutter's group who have all flown to meet them in the Palace, Teir quietly departs, promising Ember that if she ever needs him he will find a way to her. All the elves except for Teir enter the Palace, and the Palace disappears as Teir watches.